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comparison include/hashtab.h @ 0:a06113de4d67

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author kent <kent@cr.ie.u-ryukyu.ac.jp>
date Fri, 17 Jul 2009 14:47:48 +0900
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1 /* An expandable hash tables datatype.
2 Copyright (C) 1999, 2000, 2002, 2003, 2004 Free Software Foundation, Inc.
3 Contributed by Vladimir Makarov (vmakarov@cygnus.com).
4
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */
18
19 /* This package implements basic hash table functionality. It is possible
20 to search for an entry, create an entry and destroy an entry.
21
22 Elements in the table are generic pointers.
23
24 The size of the table is not fixed; if the occupancy of the table
25 grows too high the hash table will be expanded.
26
27 The abstract data implementation is based on generalized Algorithm D
28 from Knuth's book "The art of computer programming". Hash table is
29 expanded by creation of new hash table and transferring elements from
30 the old table to the new table. */
31
32 #ifndef __HASHTAB_H__
33 #define __HASHTAB_H__
34
35 #ifdef __cplusplus
36 extern "C" {
37 #endif /* __cplusplus */
38
39 #include "ansidecl.h"
40
41 #ifndef GTY
42 #define GTY(X)
43 #endif
44
45 /* The type for a hash code. */
46 typedef unsigned int hashval_t;
47
48 /* Callback function pointer types. */
49
50 /* Calculate hash of a table entry. */
51 typedef hashval_t (*htab_hash) (const void *);
52
53 /* Compare a table entry with a possible entry. The entry already in
54 the table always comes first, so the second element can be of a
55 different type (but in this case htab_find and htab_find_slot
56 cannot be used; instead the variants that accept a hash value
57 must be used). */
58 typedef int (*htab_eq) (const void *, const void *);
59
60 /* Cleanup function called whenever a live element is removed from
61 the hash table. */
62 typedef void (*htab_del) (void *);
63
64 /* Function called by htab_traverse for each live element. The first
65 arg is the slot of the element (which can be passed to htab_clear_slot
66 if desired), the second arg is the auxiliary pointer handed to
67 htab_traverse. Return 1 to continue scan, 0 to stop. */
68 typedef int (*htab_trav) (void **, void *);
69
70 /* Memory-allocation function, with the same functionality as calloc().
71 Iff it returns NULL, the hash table implementation will pass an error
72 code back to the user, so if your code doesn't handle errors,
73 best if you use xcalloc instead. */
74 typedef void *(*htab_alloc) (size_t, size_t);
75
76 /* We also need a free() routine. */
77 typedef void (*htab_free) (void *);
78
79 /* Memory allocation and deallocation; variants which take an extra
80 argument. */
81 typedef void *(*htab_alloc_with_arg) (void *, size_t, size_t);
82 typedef void (*htab_free_with_arg) (void *, void *);
83
84 /* This macro defines reserved value for empty table entry. */
85
86 #define HTAB_EMPTY_ENTRY ((PTR) 0)
87
88 /* This macro defines reserved value for table entry which contained
89 a deleted element. */
90
91 #define HTAB_DELETED_ENTRY ((PTR) 1)
92
93 /* Hash tables are of the following type. The structure
94 (implementation) of this type is not needed for using the hash
95 tables. All work with hash table should be executed only through
96 functions mentioned below. The size of this structure is subject to
97 change. */
98
99 struct htab GTY(())
100 {
101 /* Pointer to hash function. */
102 htab_hash hash_f;
103
104 /* Pointer to comparison function. */
105 htab_eq eq_f;
106
107 /* Pointer to cleanup function. */
108 htab_del del_f;
109
110 /* Table itself. */
111 void ** GTY ((use_param, length ("%h.size"))) entries;
112
113 /* Current size (in entries) of the hash table. */
114 size_t size;
115
116 /* Current number of elements including also deleted elements. */
117 size_t n_elements;
118
119 /* Current number of deleted elements in the table. */
120 size_t n_deleted;
121
122 /* The following member is used for debugging. Its value is number
123 of all calls of `htab_find_slot' for the hash table. */
124 unsigned int searches;
125
126 /* The following member is used for debugging. Its value is number
127 of collisions fixed for time of work with the hash table. */
128 unsigned int collisions;
129
130 /* Pointers to allocate/free functions. */
131 htab_alloc alloc_f;
132 htab_free free_f;
133
134 /* Alternate allocate/free functions, which take an extra argument. */
135 void * GTY((skip)) alloc_arg;
136 htab_alloc_with_arg alloc_with_arg_f;
137 htab_free_with_arg free_with_arg_f;
138
139 /* Current size (in entries) of the hash table, as an index into the
140 table of primes. */
141 unsigned int size_prime_index;
142 };
143
144 typedef struct htab *htab_t;
145
146 /* An enum saying whether we insert into the hash table or not. */
147 enum insert_option {NO_INSERT, INSERT};
148
149 /* The prototypes of the package functions. */
150
151 extern htab_t htab_create_alloc (size_t, htab_hash,
152 htab_eq, htab_del,
153 htab_alloc, htab_free);
154
155 extern htab_t htab_create_alloc_ex (size_t, htab_hash,
156 htab_eq, htab_del,
157 void *, htab_alloc_with_arg,
158 htab_free_with_arg);
159
160 /* Backward-compatibility functions. */
161 extern htab_t htab_create (size_t, htab_hash, htab_eq, htab_del);
162 extern htab_t htab_try_create (size_t, htab_hash, htab_eq, htab_del);
163
164 extern void htab_set_functions_ex (htab_t, htab_hash,
165 htab_eq, htab_del,
166 void *, htab_alloc_with_arg,
167 htab_free_with_arg);
168
169 extern void htab_delete (htab_t);
170 extern void htab_empty (htab_t);
171
172 extern void * htab_find (htab_t, const void *);
173 extern void ** htab_find_slot (htab_t, const void *, enum insert_option);
174 extern void * htab_find_with_hash (htab_t, const void *, hashval_t);
175 extern void ** htab_find_slot_with_hash (htab_t, const void *,
176 hashval_t, enum insert_option);
177 extern void htab_clear_slot (htab_t, void **);
178 extern void htab_remove_elt (htab_t, void *);
179 extern void htab_remove_elt_with_hash (htab_t, void *, hashval_t);
180
181 extern void htab_traverse (htab_t, htab_trav, void *);
182 extern void htab_traverse_noresize (htab_t, htab_trav, void *);
183
184 extern size_t htab_size (htab_t);
185 extern size_t htab_elements (htab_t);
186 extern double htab_collisions (htab_t);
187
188 /* A hash function for pointers. */
189 extern htab_hash htab_hash_pointer;
190
191 /* An equality function for pointers. */
192 extern htab_eq htab_eq_pointer;
193
194 /* A hash function for null-terminated strings. */
195 extern hashval_t htab_hash_string (const void *);
196
197 /* An iterative hash function for arbitrary data. */
198 extern hashval_t iterative_hash (const void *, size_t, hashval_t);
199 /* Shorthand for hashing something with an intrinsic size. */
200 #define iterative_hash_object(OB,INIT) iterative_hash (&OB, sizeof (OB), INIT)
201
202 #ifdef __cplusplus
203 }
204 #endif /* __cplusplus */
205
206 #endif /* __HASHTAB_H */